An electrochemical sensor array can provide information about the spatial and temporal distribution of chemicals in liquid turbulent plumes. Planar laser induced fluorescence (PLIF) and amperometric sensor arrays were used to record signals from modulated chemical plumes released into a recirculating aquatic flume. Coherence analysis was applied to extract the frequency components contained in the sensor response. Effects due to release distance, modulation frequency, and array orientation were investigated. This study has demonstrated that frequency encoded information can be extracted from a turbulent chemical plume using an array of amperometric sensors with optimized three-dimensional geometry and tuning.

The monitoring of water distribution systems (WDSs) has been a very popular subject of study since the terrorist attacks of September 11, 2001, and the subsequent passing of laws motivating the study of WDS monitoring to provide system protection in the event of a terrorist attack. Inhibiting many WDS monitoring studies to date is the large amount of computational expense required to conduct meaningful studies, especially for larger WDSs that are of most interest. In this study, methods were developed to determine the "importance" of WDS nodes in being considered as locations for sensors used to monitor a WDS in order to make sensor placement optimization more efficient. Single-objective protection goals considered individually in optimization were maximizing detection likelihood, minimizing expected detection time, and minimizing expected contaminated demand volume. A multiobjective protection goal accounting for all three single-objective goals concurrently was also considered; the formulation of the multiobjective optimization problem was intended to minimize tradeoffs among individual protection goals. Sensor placement optimization was carried out with the Iterative Subset Search Method (ISSM) employing genetic algorithms developed in this work; ISSM used nodal importance rankings to search a small subset of nodes for the optimal solution initially then broadened the search incrementally until convergence to a best solution occurred. To demonstrate the effectiveness of the methods developed, sensor placement was performed according to each of the protection goals for three study systems--one small and two large--and a variety of attack conditions. Desirable sensor node solutions that provided for significant protection were found in all cases, and in many cases sensor placement results were comparable to or better than those of other works. Nodal importance narrowed the search for optimal sensor nodes to a relatively small proportion of WDS nodes in most cases.

This thesis will characterize the use of HFAPNB and PHOST as a sensing layer material for a fully integrated multi-mode interferometric evanescent waveguide. The compatibility of HFAPNB and PHOST with standard CMOS and MEMS processing allowed us to explore their characteristics for sensing different analytes which included water, methanol, isopropyl alcohol, and benzene. The relative sensitivity of the polymer HFAPNB and PHOST to different chemicals has been quantified and related to a refractive index shift and thickness change of the polymers. Diffusion coefficients have also been quantified for both polymers and interaction models for each polymer and analyte has been determined to predict the concentration of a mixture of analytes.

Thesis (Ph.D.)--Tufts University, 2001. / Adviser: David R. Walt. Submitted to the Dept. of Chemistry. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Systems Science and Industrial Engineering, Thomas J. Watson School of Engineering and Applied Science, 2007. / Includes bibliographical references.

Dissertation (Ph.D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographic references.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: King, William; Committee Member: Graham, Samuel; Committee Member: Hesketh, Peter

Thesis (M.S.)--Rochester Institute of Technology, 2005. / Typescript. Includes bibliographical references (leaves 109-113).

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2005. / Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2006.